The cloth prevents the drill bit to dig into the metal without the need of changing the rake angle.
How to drill a hole in sheet metal.
For the cleanest hole clamp a second piece on top of the metal making a sacrificial sandwich.
If the point is even with the outer tips of the drill you cannot pick up you mark and the drill will walk around the surface as you try to drill the hole.
Hard metals like steel and larger drill bits require even slower speeds.
Make a dimple drill bits can be reluctant about metal.
Now drill the final hole at the desired diameter with the corresponding twisted drill bit but put a cloth between the bit and the metal.
Using a black marker pen mark where you want to start drilling.
To 3 16 in you can drill through most metals at 3 000 rpm.
The pilot hole will help you positioning the drill bit and than just drill as usual.
Twist drills are great.
It s not as effective but much simpler.
Since this is a small hole a normal drill bit will work well in the sheet metal without extra precautions.
A point at the end of the drill to place in your center punch mark to start.
Your first step should always be to locate the centers of all the holes you will need to.
With a small twist bit 1 16 in.
When drilling thin sheet metal clamp the metal over a piece of sacrificial plywood or other flat sheet good like mdf or particleboard to help prevent the bit from tearing up the hole.
Always use a clamp or three.
You could also make a small dent using a hammer and.
The scallop you see on the right side of the drill in these views is the relief angle that must be.
In general it s a good idea to drill through metal using as slow a speed as possible using a drill bit for metal.
Drill a small pilot hole in the required location 3mmø with the drill spindle stopped locate the folded cloth centrally over the hole and fit the large diameter drill to the machine no need to use further pilot holes if you use the correct speeds and feeds.
You ll need to start by securing your metal sheet in place before.